The effect of surface chemistry modification of titanium alloy on signalling pathways in human osteoblasts

Establishing and maintaining mature bone at the bone–device interface is critical to the long-term success of prosthesis. Poor cell adhesion to orthopaedic and dental implants results in implant failure. Considerable effort has been devoted to alter the surface characteristics of these biomaterials in order to improve the initial interlocking of the device and skeleton. We investigated the effect of surface chemistry modification of titanium alloy (Ti–6Al–4V) with zinc, magnesium or alkoxide-derived hydroxy carbonate apatite (CHAP) on the regulation of key intracellular signalling proteins in human bone-derived cells (HBDC) cultured on these modified Ti–6Al–4V surfaces. Western blotting demonstrated that modifying Ti–6Al–4V with CHAP or Mg results in modulation of key intracellular signalling proteins. We showed an enhanced activation of Shc, a common point of integration between integrins and the Ras/Mapkinase pathway. Mapkinase pathway was also upregulated, suggesting its role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the Mg and CHAP modified Ti–6Al–4V. Thus surface modification with CHAP or Mg may contribute to successful osteoblast function and differentiation at the skeletal tissue–device interface.     

Detachable shape-memory sewing ring for heart valves

The novel sewing ring concept consists of a detachable ring snap connection between valve housing or stent and suture cuff. The suture cuff itself is a memory metal ring of nickel-titanium (NiTi) that is embedded within a textile fabric torus. After a special training program the ring can assume two geometric shapes when alternately cooled and heated. Due to this physical property, the sewing ring can be safely fixed within a groove of the housing or stent by changing between room and physiological temperature. This allows the surgeon first to implant the sewing ring followed by arbitrary positioning and final fixation of the valve by the shape-memory effect. Additional advantages are an increased stiffening of the valve base for minimizing potential leaflet dysfunction, and reduced time and risk of implantation, particularly when a reoperation is necessary.     

The effect of sandblasting treatment on endurance properties of titanium alloy hip prostheses

Sandblasting is a procedure of increasing surface roughness. This treatment is common in the orthopedic field. An increased roughness may affect the endurance limit of the material. This study investigates the effect on the endurance limit of the Ti6Al4V due to two different sandblasting treatments: fine sandblasting and coarse sandblasting. Twenty hip stems, 10 finely sandblasted and 10 coarsely sandblasted, were tested under sinusoidal fluctuating bending. The staircase method was used to estimate the endurance limit of the material. The results show an important reduction in the endurance properties up to 40% for the coarsely sandblasted specimens. The failures of the sandblasted specimens were not due to material defects. Rather, the decreased endurance strength of the sandblasted stems was caused by surface defects, which act as crack initiators. By modulating the roughness with an appropriate sandblasting treatment, it is possible to limit the reduction in the endurance limit of the alloy.     

镍钛记忆合金环抱器治疗锁骨骨折利弊

锁骨骨折是临床较常见的骨折之一.近几年应用镍钛记忆合金环抱器治疗锁骨骨折的报道较多,但报道其优点较多,很少谈其缺点及不足.2005年1月～2007年1月,我科收治24例锁骨骨折患者,采用镍钛记忆合金环抱器治疗,笔者对其利弊进行分析如下.     

Prerequisites for magnetic resonance image-guided interventions and endoscopic surgery

Summary

Our purpose was to evaluate technological prerequisites and predural principles that enable easy, precise and reproducible magnetic resonance imaging control of interventional procedures, such as biopsy and aspiration of neoplasm or local interstitial drug instillation in adequate time and with the required safety. New MR compatible needles, trocars/cannulae, endoscopes and ancillary equipment were developed or evaluated in collaboration with industry. Sequences, study protocols and the strategies of performing the procedure within the environment of an interventional MRI suite were conceptualized and tested. In 80 patients interventions such as aspiration biopsy, peridural corticoid injection at spinal nerve roots and intratumoural ethanol instillation were performed successfully.     

镍钛形状记忆接骨器促进骨折愈合实验研究

目的：对比镍钛记忆合金接骨器（Swan-like memory-compression connector,SMC）与加压接骨板（compression plate,CP）固定下骨折愈合过程的血管形成，探讨SMC内固定下骨折愈合血管形成的特点。方法：25只家犬两侧股骨中段横形截骨，左侧以SMC、右侧以CP固定，术后2、4、8周行X线摄片、光镜、电镜观察。结果SMC组骨折部位血管长入时间明显提前，血管数量较丰富、发育程度优于CP组，8周时SMC组即可见完整血管内壁，内皮细胞发育成熟。结论：与CP相比，SMC组骨折端血管长入的时间较早，保证骨折愈合所需营养成分的供给，有利于促进骨折愈合。     

钛合金板置入在颅骨缺损修复中的应用

目的:探讨钛合金板置入在颅骨缺损修复中的应用。方法:对12例颅骨缺损的患者先进行三维CT检查,设计个性化的钛合金板置入以修复颅骨缺损。结果:本组患者均愈合良好,无感染、钛板外露及头皮血运障碍,避免了再次手术。结论:应用钛合金板修复颅骨缺损,具有良好的生物学力度,抗击性强,并发症少,生物相容性好等优点,可获得较好的治疗效果。     

形状记忆合金网状支架治疗良性高危前列腺增生症

目的 探讨形状记忆合金网状支架治疗良性高危前列腺增生症的疗效。方法 回顾分析1995年11月至1998年11月应用镍钛形状记忆合金网状支架治疗高危前列腺增生症35例临床资料。结果 34例一次治疗成功,30例术后立即自行排尿,4例术后3天恢复自主排尿,总有效率97．1％(34／35)。结论 镍钛形状记忆合金网状支架治疗前列腺增生症安全、有效、近期疗效满意,远期疗效正在观察中。     

含钛合金及Ni-Cr合金与瓷粉结合强度的实验研究

目的:研究含钛合金(4%～6%)[熔附HeraCeramJC瓷粉(A1组)和Vita瓷粉(A2组)]、HeraCeram公司的Ni-Cr合金[熔附HeraCeramJC瓷粉(B1组)和Vita瓷粉(B2组)]及西北有色金属厂的Ni-Cr合金[熔附HeraCeramJC瓷粉(C1组)和Vita瓷粉(C2组)]的金-瓷结合强度,为临床工作提供参考。方法:运用三点弯曲法对各组的金-瓷结合强度进行测试,并对金-瓷结合界面进行电镜观察分析。结果:电镜显示各组瓷粉均与金属基体结合紧密,无明显气泡、中间层等缺陷。结合强度:A1组:(41.08±2.98)MPa,B1组:(46.05±3.16)MPa,C1组:(44.04±3.69)Mpa;A2组:(42.29±3.38)MPa,B2组:(42.05±3.26)MPa,C2组:(47.47±2.92)MPa。①HeraCeramJC瓷粉与3种合金结合的结合强度比较:B1>A1(P<0.05);B1>C1、C1>A1(P>0.05)。②Vita瓷粉与3种合金结合的结合强度比较:C2>A2、C2>B2(P<0.05);A2>B2(P>0.05)。结论:本实验表明临床常用的3种非贵合金与瓷粉的金-瓷结合强度均大于ISO所要求的基本值25MPa,但各组间还存在一定差异,为临床工作中根据患者的具体情况选择合适的烤瓷修复基底材料和瓷粉提供实验依据。     

记忆合金环抱器治疗掌骨干骨折

2002年3月-2005年2月,我院采用切开复位镍钛形状记忆合金环抱器治疗掌骨干骨折49例,取得了较好疗效。